A.Holloway (Electronics)
Professional Product at Industrial Prices.
 
 
 PRODUCTS
 
This work has been mainly custom-built equipment, so we do not carry a wide range of
standard products as such. Following is a list of some of our more commonly used items and designs:-
 
Industrial Video/Audio distribution amplifier (type 887)
Professional Video and Audio distribution amplifiers (type 189 video and 988 audio)
8-input 8-output Video/Audio matrix (type 884)
16-input 24-output matrix (separate video and audio frames, each 6U)
Monitoring switchers (up to 150-input in a 3U frame) for video or audio
24-input 16-output "industrial" matrix
Special purpose switchers
Video pattern generators
Keyers
General
Customising Options
 
 
 
Industrial Video/Audio distribution amplifier (type 887) 
 
This is housed in a "utility" box with looping inputs and six outputs (video plus two audio). This DA operates on AC mains (150 to 250v without adjustment), and has no external controls except a video terminating switch. You may have come across its predecessor (DA-282) which Andrew designed originally for the set-up of Chroma Video (where he was Engineering Director), and was then sold by Johannesburg Video (later Avvid) - it must since then have become the most "pirated" video design in SA! This unit is in use in many TV facilities throughout the country, and has spawned a number of derivatives offering alternative facilities (component video etc.). 
 
 
Professional Video and Audio distribution amplifiers (type 189 video and 988 audio)
 
These rack-mounted modules (similar in concept to the Avitel range) have 6 or 8 outputs each. Video DA's have built-in gain/EQ adjustment plus selection of composite/non-composite/average level DC restoration. Up to 16 modules may be mounted in a 3U 19-inch rack frame - two modules may be replaced by a power supply module (type 890). Provision is made to install two PSU's in one rack, or to interconnect racks enabling "redundant" supply operation for optimum reliability. These units are in use in a number of locations throughout the country (Six Street Studios, both Johannesburg and Cape Town, Trilion, ZSE-TV, Trinity Broadcasting, Video Cassette Reproductions, Kinnor Centre, Video Duplications, Camera Store, etc.). 
 
 
8-input 8-output Video/Audio matrix (type 884)
 
This is a modular "industrial" design with options for mono or stereo, balanced or unbalanced audio, etc. Variations are in use in many duplicating facilities (ZSE-TV, Video Lab, VCR, CopyVision, etc.) and educational/broadcast facilities (Wits, Bop-TV, etc.).  
  
 
16-input 24-output matrix (separate video and audio frames, each 6U)
 
A professional unit with standard "double Eurocard" PCB's, gain/EQ adjustment on each video output, balanced audio, etc. Control is by a parallel data bus operated by computer or manual panel(s) as required. 
 
   
Monitoring switchers (up to 150-input in a 3U frame) for video or audio
 
A "professional" modular style with "Eurocard" PCB's, gain/EQ adjustment, audio level adjustment, etc.  
 
 
24-input 16-output "industrial" matrix
 
Again, separate frames for video and audio (each one 3U).  
 
 
We have designed and manufactured special purpose switchers (e.g. for component video or for computer R-G-B applications), as well as video pattern generators, keyers etc. for specific customer applications.  
 
For ease of maintenance the designs have all active circuitry on plug-in printed circuit boards - these may be of the "Eurocard" type (i.e. front panel access) in the "professional" designs, or accessible by removing a cover in the cheaper "industrial" designs. Please note that all components used are bought locally and (with a few minor exceptions) are multiple-sourced. No difficult-to-get (or even difficult-to-see!) special integrated circuits, surface mount components etc. are used, so it is not necessary to worry about spares holdings, sophisticated test equipment, or long down-times in the unlikely event of a fault developing. 
 
Whilst the basic requirements for video and audio routing systems are well known, note that we are able to customise a large number of options. These include:-  
 
stereo/mono audio (or additional channels for timecode, control etc.)   
adjustable input levels (where source output levels cannot be normalised)   
adjustable output levels (where destination input levels cannot be normalised)   
selection of clamped or restored video DC output levels   
adjustable cable equalisation for video outputs   
balanced or unbalanced audio inputs/outputs   
terminated or loop-through video inputs   
additional buffered outputs   
input/output connector types as required   
          etc., etc. ...  
  
Overall system complexity and cost can be significantly reduced by some or all of these "extra" facilities being incorporated within a single structure instead of being added externally. 
 
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Tel. +27 12 253-2778
 
Email Us!
holloway@icon.co.za
 
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